First of all I'll mention that I'm really big on IBM BS boards, but in the last few months I've gotten into looking for older spherical key boards - because they just look so cool. It seems a not small percentage of the boards I've come across are older KeyTronic foam and foil.
I understand some people just don't like linear switches but beyond that there seems to be some special hate for KeyTronic foam and foil. Yes, they are a pain in the arse initially because, as many have noted, the foam has usually turned to brown gunk and has to be replaced - but once its done, I've found them to be rather nice switches. I'm not claiming a lot of experience since I've only rebuilt three of these boards (a Tandem 6530, a Westinghouse W1642A and a TRS-80 Model II) but I really like all three. I did complete foam and foil replacement and xwhatsit Model F to USB on the Westinghouse and TRS-80 Model II (the Tandem didn't need new foam) and I think they're nice, rather smooth linear switches - and I love the keycaps and the sound they make when typing. I really don't find them "mushy" either - the springs seem to dominate the feel of the switches in my opinion.
So there I've said it - I like KeyTronic foam and foil.